1. Field of the Invention
This invention relates to a protective shield for a solar energy concentrator.
2. Description of the Prior Art
The pamphlet "The Stirling Engine Solar Parabolic Dish System" issued by United Stirling October 1982 shows concentrators of known design located at Edwards Air Force Base in California. Here solar energy is concentrated by a parabolic dish reflector. The heat is focused onto a Stirling Engine, which then converts the heat to mechanical power output to drive an electric generator. The parabolic reflector has a diameter of 11 meters and concentrates a solar energy of about 90 kW.
In case of engine failure causing a stop in the power conversion the energy supply should be stopped immediately in order to avoid damage to the Stirling engine heater head.
On page 6 of the above mentioned pamphlet a solar Stirling engine has been shown comprising two water cooled shutter plates, which may be moved into a position in which they block the insolation through an aperture opening of a receiver cavity.
The cooling system necessary to absorb about 90 kW energy is rather heavy and expensive also because it must be reliable in operation.